Automatic control equipment



July.21,- 1931. P. MATHEWS, JR

' AUTOMATIC CONTROL EQUIPMENT Filed Sept. 17, 1929 Inventor;

Paul Mathews J1. WWW

Fig.2.

His Attorne g.

' Patented July 21, 1931 wire fsgrrs mom . PAUL ne'rnnws, or" nnnronn, ENGLAND, Assrenon To GENERAL ELnomnIo qolir- AW A. e r flewez ye vo s.

AUTOMATIC oonrnor EQUIBMEfiT I i Application filed September 1 7 1929. Serial No. 883,297.

,' My invention; relates to automatic control I equipments and part-icularlyto automatic con- 7 trol equipments formercury arcrect hers and ts role ect 15 130 prov de an improved arrange- Inent of apparatus for automaticalt y thenplacingthe rectifier in service whereby the rectifier equipment [is shut down and locked out if the arc is not established ithin a p edete m e t m nt v 'My invention ,will be better understood from the following description When taken in connection With the accompanying draW-' ings and its scope will be pointed out in the 7, Referring to the arrangement shown in Fig; 1,1 represents a mercury arc rectifier w i h. is ar anged to be i te nn c e ;tvveen an alternating current supply circuit 2 and aldir'ect current load circuit-,3 by means v of suitable switches at and?) respectively. In order to obtainthe desired direct; current :930 i andthe alternatingcurrentsupply circuit 2.

ye teg from th e tifier a Po r n former 6c is connected between the rectifier 1 T ee en y wind gs v01E th pow r tran fformer 6 are connected in'fstar and the nenvtrals' thereof are }connectedthrough an interphase transformer 7; and a smoothing reactor ,8 to the negative side 1 of the direct current ve rcuit 3 wh ch, in h ip r ieuler mb dime shown i the dr rwing ii h gre n The rectifier 1 comprises a pl lrality of and a cathodell ivvhich-islconnected'to the pos t ve s e of the irect current c c 3 bythe switch 5. I

v. {Due to the characteristics of, the mercury are u rent flows r me y a Q elO ethe ca od 11 h n t voltage of t a ej eis c h ghertha'n ha a the: cathode u e eu ren never flowsinthe e er e re o l xstart-' ing an arc in a mercury arc recti er and anode connected to one end of separate s ndary' i gr the new r t an fermer a 5 the t r en ef Which s enneete -te he, ee i r gree e eide f t e eeseireui by meansof the interphase transformer '7 e 'e e e \8, e a d d ri pe tien if each cycleiof-the lternating current has ,a P n i g e th elj y on of heether anodes andduring that period allows acuprent to flow to the cathode across the'rnercupy fgg are after it has once been started. I

v AS th m cu y a i no s ietertin s e formv 10 e s abl s ng m ans, er: em f which are W l known" in i heert, has to be provided. In the'pres ent embodi ment of my invention I have shown the rectifi r s be n P ov d wi h en euxi eryer are striking mo 1 3 r es a ishing the h s ene 1 's.n me y eld em; o n a emen wit th -m y y me ns 9i iasp g eandis ang d to be m ved. into en a men i i' h m ury y oi a s l noid 1. w i h, en ne g ze p aces the pring 114 ,uncl ,;t 1.1 9n- When he anode en elee th me eury e i euit ,f emeieuitfeblee e f u ent, ehe n i the dra ngs as the generator w of a motor generator S 1 5 mp tedthreugh cen r relay Whi n ene g zed, fieets the .de'

'ene 'e e i n le -the soleno 15.139 that the p ing; 14mm the e tine'enode out pi e ing e nthe ec ifier After the ex iting r n est b h the swi ches 4; and

ere suc ss vely sed e that eu rrent flows I from h anode 1 t th ea hede l ,;e,f.the

rectifier and in this manner energy is trans-c ccth n ercnrygandthereby e tablishes an exrr em heial rn t ng u rent supply circuit 2 to the direct current load circuit wed- 1 which e nnedted oi h e ee de y mina of the P r transfermer 5 In accordance with my invention, 1 ro- ZDD yide' en improved arra ge en of apparatus forcontrolling the automaticstartingof the rectifier lvvhereby if the are establishing m an f i t e blish an ar within a predetermined tinie or for any reasonthe automatic st ting pe at en: is not completed Within a predetermined timethe equipment c f w eeptun er ebn m'el eend tiion Since eeeh i the w nee, th znenm l trol "device 21.

starting and stopping of the rectifier is eiiected by the closing and opening of a hand 'switch'2O in the circuit of a master con- Any other suitable control means, examples of which are well known in V theart, may be employed instead of or in addition to the manually controlled switch 20 to control the energization of the master relay 21 to effect the starting and stopping of the rectifier 1.

V As shown in the drawings, the closing of the control switch 20 completes the circuit'of the master control relay-21 across -a suitable conthetprimary of which is connected'across the supply .circuit'2. The energization' of the trol circuit 22 which is connected to the secondary winding of a control transformer 23 mastercontrol relay '21" initiates the starting of the motor 24 of the motor generator set 17 so that theoperation of the arc establishing means is initiated. The energization of the master relay 21 also initiates simultaneously with the initiation of the arc establishing means but independently of whether or 'notthe arc establishing means establishes an arc, the "operation of a timing device 25 which controls the closing of the switch 4 and the locking out of the equipment. As shown in the drawings, the timing device 25 comprises amotor driven timer 27 the motor 26 'ing each revolution of the timer 27 it eifects,

in case an exciting arc has been established,

a predeterminednumber of closures of the switch 4 with predetermined timeintervals .between successive reclosures by successively effecting the energization of the control relays 32 and 33, which in'turncontrol'the currentof the closing coil'52 of the switch 4. The closing of the switch 4 efiects the completion of an energizing current for the closing coil 54 and closes the switch 5;

In case the arc establishing means fails to establish an are or some other abnormal condition occurs so that the switch 4 is not closed 7 55 within a predetermined'time after the operatlon of the master relay 21 is efiected the timer 27 is arranged to efiect the operation of v a lockout relay 34. The lockout relay 34 when energized opens the energizing circuit of the master relay '21 which when deenergized efi'ects the shutting down of the automatic control equipment.- The lockout relay. isarranged" in any suitable manner, ex-

amples of'whichare, well known in the art,

so that it prevents the energizing circuit of the master relay 21 from being subsequently completed by the control switch 20 until after the lookout relay has been'reset manually. As shown in the drawings, the lockout relay 34 is of the type which is held in its energized posit-ion by a manually releasable latch 35. i e

In order toprotect the rectifier a'ga-inst overloads and are backs, the switch 4is provided with the overload trip coils 36 and 37 which are respectively energized by means of the current transformer 38 and 39 so that they are energized in response tothe currents flowing-in two of the phases of the supply circuit 2. Since the inrush or transient current of the power transformer 6 at the instant the switch 4 is closed may, under normal conditions be severaltimes normal currentand 'the closing of the switch 4 to remove the short-circuit from around the trip coils 36 and 37 and thereby render the trip coils operative to effect-the opening of the switch 4 after it has remained closed mined length of time. r

The operation of the arrangement shown in Fig. 1 is as follows: lVhen it is desired to place the rectifierin operation the control switch 20 is closed so that the coil of' the for a predetermaster relay 21 and the contacts 41 ot'thelockout relay 34in series therewith are connected across the control circuit 22. The master'relay 21jby'closing its contacts 42 connects the motor 24of the motor generator set 17 across thef supply circuit'22 so that.

the starting ofthe motor generator ,set 17 is effected. As soon as the voltage of the generator 16 ofthe motor generator set builds up to a predeterminedvalue, the solenoid 15 of the arc' establishing means is energized suificiently to move the striking anode '13 into engagement with the mer'cury of the rectifier. The energizing circuit of the solenoid 15 includes the contacts 43 of the control relay 18. As soon as the striking anode 13 engages the mercury current flows through the coil of the control relay 18 which is connected in series'with the striking anode 13 and the cathode 11 across the terminals of the generator 16. The current through the relay 18 causesthis relay to open its con .tacts- 43 and close its-contacts Theopen- -ing of the contacts 43 which are in the'circuit of the solenoid effects 1 the deenergization "of the solenoid 15 so that the spring 14 moves the starting anode 13 out of engagement with the mercury and thereby establishes are in the rectifier; Since the arcresistance is."

I very low, suflicient current flows throughthe arc hetween the starting anode: 13d and the vmercury to maintain-thecontrol relay 18 in its energized position; In order to limit-the I current through therelay 18 -to a predeter L *whetheror not the starting arc isestahlished ilm-the rectifier, energizing circuit for the "release magnetot the timing device 25 control circuit-22, alsofincludes the auxiliary is closed; The energization of the "release magnet 30, draws thestop 28' out of engage ment with the projection 29 so that the con: stantly energized motor 26 can drive the timer I Within a short atterthe release magnet 30 ise'nergi-zed, during which time the starting arc is established under normal conditions, the timer 27 closes its contacts 48 "and completes a'crossthe control circuit 22 an energizing circuit for the control relay 32.

1 This energizingcircuitals'o includes the contacts 42 of the master relay 21 and the auxilimy contacts 47 of the switch 4i; *The control relay 32 by closing its contacts 49mm. pletes'a lockingcircuitfor itself whichis 3 independentof thecontacts? 48 of the timer 27. Subsequently, the timer: 2'? opens its contacts and? closes 'its'j contacts 50 and thereby/comp etes across the control circuit 22, an energizing circuit for the control 're-' 2 layv33 provided a'n 'arc has beeniestahlished linitherectifier 1 so th'at the relay, 18 is ener- 1 gizecl.- The energizing circuit of the control relay 33 is from one sided? the control "cireuit 22th rough the coil of the m yeamntacts 440i the control relay 18, contacts 50 c of the timer 27, contacts 49 of the control rev f 4 across the control-circuit: I The energization of the closing coil 52 effects the co ntacts 53f c fompletej an' energizing, circuit 7 for'theclosingcoil 54 of thefswitch 5,;across closing or the switchi4 so that the meter 1 connected to the supply circuit 2. W n Switch 7 4" closes, its auxiliary the direct, current terminals of the rectifier,

direct current load vcircuit 3 as above azpredetermined value; The?circuit of ithelclosing coil 54 "also includes intheicontactstiiotthe,rnasterwrelay2li,.

motor 26 in whichcposition it is stopped by at the auxiliary Contacts 47 of-the; closed This circuit which is connected across the,"

*olpening itsg'contacts '42 and 55', eifects the p deenergizationi of the low voltage trip eoil fl When the switch 4 closes, its auxiliary'contacts 5,6'complete, across-the control circuit 22, anlenergizing'circuit for the'control re-' lay 40 which removes the short-circuitsirom around" the trip coils'36 and37 by opening its contacts 57 and'58;and an energizing cir-c cuit'fo-r the under-voltage'trip coil 59,;for theswitch4. I I r i r Ifithe switch 4 remains -closed,'the}timer 27 isreturned to its normal position by, the

the stop 28 engaging the projection; 29,- since the circuit of the release magnetSQ is alien c switch4 V If at any time the switch 4 is'opened 'for any reason while the master relay 21- is energized, the closing of the auxiliary contacts 47, of the switch 4 effects the e'nergization of the release magnet 30 so thatthetimer 27 is. operated by the motor 6 toefi'ect the re vclosing of the switch 4 in themanner above described, If the switch 4 does notremain closed after the first reclosuretherofthe timer 27 is arranged to eflect a plurality of its" lockout position in which positiomthe timercontacts 61 are clos'eda circuit which also includesthe contacts 42 of thefrnaster relay 21 is completed, across the control cir- 'cuit 22,1501 the lookout relay 34. Thevl'ock- -.out relay 34 by opening itscontacts in the energizing circuit of the master relay 21 effects the deenergization ofthemasterrelay H and looks out the equipment against a restartby rendermgthe master relay unre sponsive to the operator or the control switch 20 until the latch'35 offthelockout relay has beenreleasedmanually;{

Sincelthe timing device, 2 qisstartedjinder I pendently of, whether or not the are establishing means establishesan arc in the recti 1:151

fier, it; will be observed; that this timing device efiects the locking out oftheequipment in casel'an arc is notestablished within a I predetermined time after the master relay 21 is energized as wellas when some other abnormal conclition preventsthe automatic switchi g equipment from effecting the'closingfof the switch 4within, a predetermined time after themaster relay 2lis energized.

Under normal operating conditions,jth e 125, .rectifier 1 is shut-down by} the 'openingofthe control switch 20, which deenergizes the master relayf21. f The master relay 21; by

as p

1 5,9 of the switch4 and the closing coil '54 of Jtheswitch 5 so that the rectifier is disconcontacts 42 of master relay 21 whichare also in the energizingcircuitbf the motor 24.

In the modification shown in Fig. 2, the circuit or the lookout relay 3e includes the aux? iliarycontacts 65 on theswitch 5 instead of v V V I 'means for effecting the closlngof said switch theauxiliary Contacts 60 on the switch 4,

fWith-this change in the connectionsof the lockout'relay 34, it"is necessary for the automatic switching equipment to complete the closing of the switch 5 as well as the closing of 'the switch 4 withina predetermined time after the masterrelay2l is energized in order 'to prevent the locking out of the control equipment. I y

While I have, inlaccordance with the patent statutes, shown and described my invention as applied to aparticular system and as embodying various devices diagramatically in-' dicated, changes and modifications will be obvious'to those skilled in the art and I, thereiore, aim in theappended claims to'cover all such changes and modifications as fallwithin the true spirit and scope of my invention.

WhatIclai'mas new and desire to secure Letters Patent of the United States, is:

' 1. In combination, an electric circuit, a mercury arc rectifier, arc establlshing means for said rectifier, a switch for connecting said rectifier to said-circuit, a timingdevice, a control device for initiating the operation of said are establishing means and said timing device,

means for efiecting the operation of said con-- trolidevice, means controlled by'said timing devlce and sald arc establlshlng means for effecting the closing of said switch it there is i 7 an arc in said rectifier at the expiration'ofa' predeterminedtime interval after the opera:

tion of ,said control device is effected, and means controlled by said timing device for renderingsai'd control device unresponsive to v the operation of the means for'efiectingthe operation thereof if said arc establishing 'means [fails to establish an are within a prerectifier to said circuit, a motor operated timer, a control device for initiating the operation of said are establishing means and the operationiof said timer independently ofthe operation of said arc. establishing means, means co'ntrollediby said timer andsaid arc establishing means for closing said switch, an'd'means controlled by said timer torrendering said control device inoperative to effect if; saidiarcziestablishingi means fails to establishing means.

lish an arc within a predetermined time interval. 1 r I 8. In combin atlon, an electric circuit, a mercury arc rectifier, arc establishing means for if it is open and an arc exists in said rectifier after a predetermined tlme v lnterval has elapsed after the operations of said arc establishing means and timer have been initiated,

and means controlled by said timer for ren dering said starting means inoperative to iniitiate the operation of said are establishing means if an arc is not establishedin said rec-i tifier within a predetermined time afterthe operation of said are establishingmeansis started. r i 1 4. In combination, an electric circuit, a mercury arc rectifier, arc establishing means for said rectifier, a switch for connecting said rectifier to said circuit, means including a motor operated timer for closingsaid switch a plurality of times with predetermined time intervals between successive reclosures of said switch and o for preventing the subsequent closing of said switch it it is notclosed within apredetermined time and means for initiating theoperationof said are establishing means and-the operation of said timer, the operation of said timer being "effected independently of the operation of said arc estab- 5. In combination, an electric circuit, a mercury arc rectlfier, arc establlshing means 1 for said rectifier, a switch for connecting'said timer, means for initiating the operation of said arc establishingmeans and the o'pera-.

eration of said are establishing means, means controlled'by said timer and are establishing means for" closing said switch apredeten mined number of times within a predetermined time interval, and means controlled by said timer and switch for rendering'said initiating means inoperative to efi'ect the op eration'of said are establishing means if said switch: is open when said'timer is in a pre determined position. v

6. In combin ationfan electric circuit, a mercury arc rectifier, arc establishing means for said rectifier, a switch for connecting said rectifier to said circuit, amotor operated .timer, means for initiating theoperation of said are establishing means andlthe operation V of said timer independently of the operation of said are establishing means, and means controlled by saidtimer ror closing said switcha-plurality, of times with -predeter m ned time intervals between" successive re closures ifthe arc is established in said rectifier Within'a predeterminedtimeinterval and i forrenderlng sald mtiatlng means-lnoperaf tivet'o effect the operation of said are es :tablishingmeans if an arc is not established 7 in said rectifier Within'fa predetermined time afterthe operation of said initiating means.

' In combination, anielectric circuit, a

.mercuryarc rectifier, arc establishingmeans 10 V rectifier to said circuit; a motoroperated for saidrectifier, a switch'for connecting said timer, means for initiatingithe operation of i number oftimes Within a predetermined time 7 r interval, if an arc is establishedfin'said recifi-I V enduring said time interval, and means con- .said" are establishing means and the'operation of said timerindependentl yof the 0p-- eration of said arc establishing means, means controlledby said timerand ar'c establishin means for closing said'svvltch a'predetermined trolledby said timer and switchfor rendering said arc establishingfmeans" inoperative if saidiswitch is openlafter saidtimerlhas been in operationifona predetermined time."

8." In combination, two'electric circuits, a

mercury 'arc rectifier; are establishing means Qfor'. said rectifier; switching means 'io r connectlng saldrectlfie'r to sa d c1rcu1ts, a filming devlce, means for imtlatlng the operat on of said are establishing means andi-the operation of said timing device independently of the operation of said are establishing means; k meanscontrolled by said timing device and arc establishing means for effecting the op eration of said switching means to'connect sa d rectlfier to said' c rcnlts after an arc has been established in said rectifier, and means controlled by said timing device and switch- I ing means for renderingsaid arc establishing 'means lnoperatlve 1f a predetermined operation of said swltchlng meanshas not been,

eifected Within apredetermineditime after the-initiation of the operationof said timing device.

In Witnesswhereof I have hereunto set my hand this 6th day of September; 1929. 

